Summary

We have seen the frequency with which goitre is associated with the psychoses—in a mental hospital receiving no cases of idiocy, one patient in every eight having some thyroid enlargement.

As to the mechanism of this association we have seen that (a), goitre is, at some time in the patient's history, accompanied by a condition of hypo- or hyperthyroidism, and that (b) either of these conditions is capable of inducing a state of auto-intoxication with mental symptoms.

My series of cases show that the nature of the psychosis is, in some degree, determined by the form of the functional disturbance of the thyroid gland, e. g., hyperthyroidism is usually associated with states of excitement, agitation, etc. (e.g., manic-depressive insanity), whereas hypothyroidism is more often associated with states of apathy and indifference (e.g., dementia præcox).

The treatment of the psychoses associated with goitre depends to some extent on the nature of the functional disturbance of the thyroid gland. If the signs point to hypothyroidism treatment by thyroid extract should be instituted. If hyperthyroidism is present the treatment should be directed to the removal of the mental element, which is now admitted to be of great importance in the ætiology of this condition. The only satisfactory method of accomplishing this is by the employment of psychotherapy.